KAAP Chapter 23

if vitamins do not provide a source of energy, what is their role in nutrition

play a role in metabolic pathways by serving as coenzymes

describe leptin and its effect on appetite

a peptide hormone produced by adipose tissue during the synthesis of triglycerides. It stimulates the satiety center and suppresses appetite

name the heat conservation mechanism that conducts heat from deep arteries to adjacent deep veins in the limbs

countercurrent exchange is in the heat conservation mechanism that results in the conduction of heat from deep arteries to adjacent deep veins in the limbs

identify the two classes of vitamins

fat soluble and water soluble

Define beta oxidation

fatty acid catabolism producing acetyl-CoA

Identify the fates of fatty acids

fatty acids may become a source of energy or a component of triglycerides, glycolipids, phospholipids, prostaglandins, cholesterol, and steroids

when and how do ketone bodies form

form during the postabsoprtive state, when lipids and amino acids are broken down in the liver. The increased concentration of acetyl CoA that results from their breakdown forms ketone bodies. Ketone bodies are not catabolized by liver cells, and they diffuse into the circulation

Define oxidative phosphorylation

generation of ATP as the result of the transfer of electrons from the coenzymes NADH and FADH2, to oxygen by a sequence of electron carriers within mitochondria

describe the role of non-shivering thermogenesis in regulating body temperature

involves the release of hormones that increase the metabolic activity of all tissues, resulting in an increase in body temperature

explain when glycolysis is important in cellular metabolism

it is important when ATP must be produced anaerobically, during peak levels of physical activity, at all times in red blood cells, or when a tissue is temporarily deprived of oxygen

how might a lack of neuropeptide Y in the hypothalamus affect the control of appetite

lack of neuropeptide Y, a hypothalamic neurotransmitter, would probably decrease appetite because it normally stimulates the feeding center

of these- carbohydrates, lipids, or proteins- which releases the greatest amount of energy per gram during catabolism

lipids

what molecule forms the common substrate for the citric acid cycle

2-carbon acetate ion, CH3COO-, which is attached to coenzyme A to form acetyl-CoA.

Identify when most of the CO2 is released during the complete catabolism of glucose

2/3s of CO2 is release in the complete catabolism of glucose occurs during the citric acid cycle

define protein deficiency disease

nutritional disorders resulting from a lack of one or more essential amino acids. Ex: Kwashiorkor

where does most nutrient absorption occur

occurs in the small intestine, jejunum

compare oxidation and reduction

oxidation: gain of oxygen, or loss of hydrogen or electrons from an atom or molecule Reduction: loss of oxygen, or gain of hydrogen or electrons to an atom or molecule

identify and briefly describe 2 eating disorders

psychological problems that result in inadequate food consumption (anorexia nervosa) or excessive food consumption followed by purging (bulimia)

what heat transfer process accounts for about 1/2 of a person's heat loss when indoors?

radiation accounts for about 1/2 of a person's heat loss indoors.

in amino acid metabolism, identify the processes by which the amino group is removed

the amino group is removed by deamination or transamination

what happens to the ammonium ions that are removed from amino acids during deamination

the ammonium ions combine with carbon dioxide to form urea which is ultimately excreted in the urine

List the products of glycolysis

2 molecules of pyruvate 2 molecules of ATP 2 molecules of NADH

compare catabolism and anabolism

Catabolism is the breakdown of large molecules into smaller ones, whereas anabolism is buildup of large molecules from smaller building blocks.

how is heat loss different between conduction and convection

Conduction: direct transfer of heat through physical contact Convection: heat loss to the cooler air in contact with the skin. The air warmed by the skin rises and it is repeatedly replaced by cooler air until there is no difference in temperature

describe the roles of LDLs and HDLs

LDLs deliver cholesterol to tissues and HDLs absorb unused cholesterol and return it to the liver.

what two coenzymes transfer hydrogen atoms to the electron transport chain

NAD and FAD transfer hydrogen atoms to the electron transport chain

briefly describe PKU

PKU is an inherited metabolic disorder resulting from an inability to convert phenylalanine to tyrosine

explain why carbohydrates are preferred over proteins and lipids as an energy source

carbs are preferred because proteins and lipids are more important as structural components of cells and tissues

why do cells make new compounds

cells make new compounds to maintain and repair structures, to support growth, and to build up nutrient reserves

most of the absorbed nutrients enter into which blood vessel

enter into a branch of the hepatic portal veins and transported to the liver

describe the role of CCK release and its effects on proteins

it stimulates the production and release of inactive pancreatic proenzymes. Enteropeptidase released from the duodenum, converts the pancreatic proenzyme trypsinogen into the proteolytic enzyme trypsin. Trypsin then converts other proenzymes to yield chymotrypsin, carboxypeptidase, and elastase. Each of these enzymes attacks peptide bonds that link specific amino acids while ignoring others. As a result, they break down proteins into a mixture of dipeptides, tripeptides, and amino acids

predict the effect of a peripheral vasodilation on a person's body temperature

it would increase blood flow to the skin and thus the amount of heat the body can lose. As a result, body temperature would decrease

what is the difference between a micelle and chylomicron

micelle: lipid-bile salt complexes (containing fatty acids, glycerol, and monoglycerides) formed in the intestinal lumen. Chylomicrons are lipoproteins formed in intestinal epithelial cells and contain newly synthesized triglycerides, cholesterol, and other lipids surrounded by phospholipids and proteins

briefly describe the citric acid cycle and explain its role

reaction sequence that occurs in the matrix of the mitochondria. In the process, organic molecules are broken down, carbon dioxide molecules are released, and hydrogen atoms are transferred to coenzymes that deliver them to the electron transport chain

define nutrition

the absorption of nutrients from food

define and describe the absorptive state

the period following a meal, when nutrient absorption is under way. During this time, insulin stimulates glucose uptake and glycogenesis, amino acid uptake and protein synthesis. Androgens, estrogens, and growth hormone stimulate protein synthesis. Glycolysis and aerobic metabolism provide the necessary ATP

explain the process of metabolic turnover

the process in which cells continuously replace their cellular components

define energetics

the study of the flow of energy and its changes from one form to another

How do the absorptive and post-absorptive states maintain normal blood glucose levels?

absorptive: insulin prevents a large surge in blood glucose after a meal by stimulating the liver to remove glucose from the circulation. post-absorptive: blood glucose begins to decrease, triggering the release of glucagon, which stimulates the liver to release glucose into the circulation

which molecule is a key reactant in both ATP production from fatty acids and lipogenesis

acetyl-CoA isa reactant molecule in ATP production and in the synthesis of most types of lipids

describe the role that hydrogen ion channels play in generation of ATP

are the passageways for the diffusion of hydrogen ions from the inner membrane space of the mitochondria to the matrix. This movement powers the production of ATP by ATP synthase

Why is digestion important?

cells throghout your body rely on the organic molecules from the food we eat to produce energy and to replenish the intracellular nutrient pool

dinstinguish between a complete protein and an incomplete protein

complete: meets the body's amino acid requirements incomplete: deficient in one or more of the essential amino acids

define balanced diet

contains all the ingredients needed to maintain homeostasis and prevent malnutrition

list the reactants required and products generated by mitochondria

continuous supply of 2-carbon substrates and O2; the mitochondrial products are CO2, H2O, and ATP

which hormone inhibits the satiety center and stimulates appetite in the short term

ghrelin

explain the role of glycogen in cellular metabolism

glycogen is synthesized from excess glucose molecules by the liver and muscle cells and it serves as an intracellular glucose reserve

compare glycogenesis and glycogenolysis

glycogenesis: the formation of glycogen from glucose glycogenolysis: the breakdown of glycogen to glucose

define insensible perpsiration

insensible perspiration is the evaporation of water from the skin and alveolar surfaces of the lungs

describe the source of intestinal gas

intestinal gas, flatus, is generated by bacterial activities in the colon when indigestible carbs stimulate bacterial gas production

Define thermoregulation

the homeostatic control of body temperature

what does the liver do with the chylomicrons it receives

the liver absorbs chylomicrons, removes the triglycerides, combines the cholesterol from the chylomicron with recycled cholesterol, and alters the surface proteins. Newly synthesized complexes are released into the blood stream as low-density lipoprotein or very low density lipoproteins

what is basal metabolic rate

the minimum resting energy expenditure of an awake, alert person.